1. Field of the Invention
The present invention relates to an apparatus for determining the permeability of a circulating band, in particular a water-absorbing dewatering band in a papermaking machine, having a nozzle from which a measuring fluid flows onto or through the band.
2. Description of the Related Art
In general, apparatuses for measuring the permeability at circulating bands are known. In these apparatuses, water is pressed through the band and the permeability of the band is determined by way of a pressure measurement. However, the disadvantage with the apparatuses known is that these require either a constant water pressure or a constant water flow. If the water pressure or water flow cannot be kept constant, the measured result is distorted.
What is needed in the art is an improved apparatus which permits an accurate determination of the permeability even in the event of variable flow conditions in the measuring fluid.